The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A hybrid electric vehicle may include an internal combustion engine and an electric motor that may operate in series or in parallel. The electric motor may be powered by a battery array and may be used to propel the vehicle at low speeds and to assist the internal combustion engine at higher speeds. The electric motor may also be driven, in part, by the internal combustion engine.
Regenerative braking occurs when the electric motor acts as a generator that recharges the battery array by recapturing kinetic energy when the vehicle is slowing or stopping. The hybrid vehicle may include both standard friction braking and regenerative braking.
In a throttle-by-wire system, a sensor detects position of an accelerator pedal of the hybrid vehicle. A vehicle control module determines a correct throttle position based on accelerator pedal sensor signals. The vehicle control module may include sub-modules that control the internal combustion engine and the electric motor based on the accelerator pedal sensor signals.
Hybrid vehicle engine efficiency may be improved by reducing pumping losses. Pumping losses refer to the energy required to pump air and fuel into an engine cylinder and to push out products of combustion. Pumping losses include losses due to throttling and losses due to aerodynamic friction. Throttling includes restricting air flow to maintain proper intake charge mass for the engine. Throttling loss is proportional to the degree of restriction of the airflow. Restriction of the airflow may be based on movement of the accelerator pedal.